This invention relates to model railroad rolling stock and specifically to a self monitoring coupler structure and to such a self-centering coupler structure which provides increased angular motion.
Model railroads, as the name suggests, are scale models of prototype railroads. Persons who use model railroads are model railroaders. A complete model railroad includes a track layout, a power source which is usually electric, non-powered rolling stock, and at least one powered engine, or powered rolling stock. The layout has defined borders inside of which model railroad track is arranged as desired. Since model railroads are often found in private houses, the layouts are often quite small. Layouts often incorporate short radius curves because short radius curves allow more complicated layouts to be squeezed into smaller spaces. The model rolling stock is modelled on prototype railroad rolling stock, and include trucks that both roll on the track and are rotatably attached to the bottom of the body of the rolling stock. Each end of the rolling stock is equipped with a coupler structure. Coupler structures allow a unit of rolling stock to be connected to an adjacent unit of rolling stock on the same track. By connecting a number of rolling stock units in series, and placing a motor equipped rolling stock at one end of the series, a model train is formed.
Coupler structures for use on model railroad rolling stock are designed to appear as realistic as possible. Prototype coupler structures include a knuckle, a shank and a receiver. Thus, model railroad coupler structures also include a knuckle, a shank, and a receiver.
The knuckle is designed to mate with similarly shaped knuckles, thereby providing the coupling effect necessary to link two units of rolling stock together. The shank is attached to the knuckle to form a coupler mechanism. The length of the shank provides the necessary spacing between the rolling stock. The shank usually is pivoted about a vertical axis allowing the two units of rolling stock to move laterally relative to each other without exerting excessive, derailing lateral forces through the coupled knuckles. The receiver is attached to the rolling stock body, and is designed to retain the shank to the rolling stock body but allow limited angular motion of the shank relative to the rolling stock. The receiver usually includes an enclosed structure with walls, an opening through which the shank is inserted, a retainer to attach the shank to the receiver, and a centering spring to center the shank relative to the receiver. Thus, when two units of rolling stock are placed on a straight section of track, the knuckles of each rolling stock will be aligned with each other so that when the rolling stock are forced together the knuckles mate. In this situation, the centerline, or longitudinal axis, of the rolling stock overlays the centerline of the track.
The coupler structure just described works well on prototype and on most model railroads, but has limitations on some model railroads. Long rolling stock units, generally in excess of 60 feet in length, require large radius curves because when a rolling stock unit passes through a curve, the ends of the rolling stock, beyond the truck axis of rotation, shifts outboard of the center line of the track. This is because the pivot points of the rolling stock trucks are located some distance from the end of the rolling stock. As the length of rolling stock increases, the distance between the end of the unit and the truck pivot point increases, causing the rolling stock centerline at the end of the rolling stock to shift further away from the center line of the track. Because the coupler mechanism has limited angular motion relative to the rolling stock body, long rolling stock units passing through short radius curves will experience lateral forces, which are induced by the coupler, which will result in the derailment of the rolling stock. The coupler mechanism reaches the limit of its angular motion before the end of the rolling stock extends far enough to accommodate the curve. Derailment may also occur on short radius S-curves as well. Thus long rolling stock units are only used on large radius curves in prototype railroads.
In model railroads, however, it is frequently desired to use long rolling stock units on short radius curves because model railroad layouts are commonly constructed with short radius curves in order to put as much track as possible on a layout to make train operation more interesting. While the model railroader could accommodate the small radius curves by only using short rolling stock on the layout, most model railroaders prefer to be able to use a wide variety of rolling stock. Thus it is required that long rolling stock units which are intended for use on such layouts be equipped with coupler structures that permit greater angular motion than the prototype coupler structure.
One known technique for providing the added angular motion necessary to use long rolling stock on short radius curves is to take the coupler mechanism referred to above, including the knuckle, shank and receiver, and attach it to a coupler subframe which is mounted concentrically with the vertical axis of the truck, and pivots about the attachment point for the truck. This technique, however, requires that the coupler subframe be precisely sized to match the length of the rolling stock unit because the distance from the end of the rolling stock to the attachment point for the trucks varies. It also is designed to match the geometry of only a particular manufacturer's trucks, thus limiting the usefulness of such technique because of the numerous parameters involved in various styles and designs of rolling stock trucks. Such a coupler mechanism mounting scheme frequently results in derailment-producing lateral forces when a train which includes rolling stock units so equipped negotiates a small radius curve, an S-curve, or travels over a turnout. The problem is aggravated when such a train is backed though such maneuvers. In addition, such mechanisms are unacceptable to serious model railroaders because they are not prototypical, nor do they appear to be prototypical.
An object of the invention is to provide a coupler structure having an increased angular motion for use on model railroad rolling stock.
Another object of the invention is to provide a coupler structure that may be readily attached to the body of model railroad rolling stock unit.
Another object of the invention is to provide a coupler structure that attaches to the body of model railroad rolling stock regardless of variations in length, design, style, or trucks used thereon.
Another object of the invention is to provide a self-centering coupler structure which is easily retrofit onto existing model railroad rolling stock units.
Another object of the invention is to provide a coupler structure with increased angular motion that is realistic in appearance.
A further object of the invention is to provide an improved coupler structure for use on model railroad rolling stock that includes a coupler mechanism attached to a coupler mount, and which fastens the coupler mount to the body of the rolling stock.
Yet another object of the invention is to provide a coupler structure having improved performance for backing long rolling stock units through small-radius curves.
The improved coupler structure of the invention is intended for use on model railroad rolling stock, which rolls on trucks attached thereto, wherein the rolling stock has a body, having an major axis thereto. The coupler structure includes a coupler having a shank and a joining mechanism for joining to a companion coupler on another piece of rolling stock located at one end of the shank. A centering structure is located adjacent the other end of the shank for maintaining said coupler in an axially aligned condition with the body axis. The centering structure includes a centering cavity formed in the shank other end and a centering mount attached to the rolling stock body.
These and other objects and advantages of the invention will be more fully appreciated as the description which follows is read with the drawings.